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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 31 |
| 3 | 109 |
| 4 | 334 |
| 5 | 937 |
| 6 | 2475 |
| 7 | 6267 |
| 8 | 15393 |
| 9 | 36976 |
| 10 | 87369 |
| 11 | 203915 |
| 12 | 471546 |
| 13 | 1082849 |
| 14 | 2473535 |
| 15 | 5627684 |
| 16 | 12765052 |
| 17 | 28887838 |
| 18 | 65260270 |
| 19 | 147233926 |
| 20 | 331842395 |
| 21 | 747355066 |
| 22 | 1682185342 |
| 23 | 3784718431 |
| 24 | 8512408455 |
| 25 | 19141037360 |
| 26 | 43032743620 |
[1,7,31,109,334,937,2475,6267,15393,36976,87369, 203915,471546,1082849,2473535,5627684,12765052, 28887838,65260270,147233926,331842395,747355066, 1682185342,3784718431,8512408455,19141037360, 43032743620] |